Flat stylus
flat stylus (see picture) are a set of plates of a certain thickness with the appropriate marking, used to measure various gaps. Also, flat feelers can be used, for example, to measure end play where the use of a dial gauge (see below) difficult.
The flat stylus set must be protected from excessive force and impact so that the stylus blades are not bent or damaged. The surface of flat probes must be kept clean and covered with the thinnest layer of oil to prevent corrosion processes.
When measuring the gap, it is necessary to choose a flat feeler gauge that will enter with little resistance between the two parts. It is recommended to have two sets of flat probes to ensure accurate measurements.
Micrometers
Micrometer - a device designed to measure linear dimensions by the absolute contact method in the region of small dimensions with high accuracy (from 0.01 to 0.001 mm), the converting mechanism of which is a screw-nut micropair.
The micrometer must be kept clean. Be careful not to drop the micrometer, as its bracket may become deformed, resulting in inaccurate measurements.
The action of the micrometer is based on the movement of the screw along the axis when it is rotated in a fixed nut. The movement is proportional to the angle of rotation of the screw around the axis. Full revolutions are counted on a scale printed on the stem of a micrometer, and fractions of a revolution are counted on a circular scale printed on the drum. It is optimal to move the screw in the nut only to a length of no more than 25 mm due to the difficulty of manufacturing a screw with an exact pitch over a longer length. Therefore, the micrometer is made in several sizes for measuring lengths from 0 to 25 mm, from 25 to 50 mm, etc. For micrometers with measurement limits from 0 to 25 mm with closed measuring planes of the heel and micrometer screw, the zero stroke of the drum scale must exactly match the longitudinal stroke on the stem, and the beveled edge of the drum must coincide with the zero stroke of the stem scale. For measurements of lengths greater than 25 mm, a micrometer with interchangeable heels is used; the setting of such micrometers to zero is carried out using a setting measure applied to the micrometer, or end measures. The measured product is clamped between the measuring planes of the micrometer. Usually the screw pitch is 0.5 or 1 mm and, accordingly, the scale on the stem has a division value of 0.5 or 1 mm, and 50 or 100 divisions are applied on the drum to obtain a reading of 0.01 mm. This reading is the most common, but there are micrometers with readings of 0.005, 0.002 and 0.001 mm. A constant axial force at the contact of the screw with the part is provided by a friction device - a ratchet. When the measuring surfaces of the micrometer are in close contact with the surface of the measured part, the ratchet begins to turn with a slight crackle, while the rotation of the microscrew should be stopped after three clicks.
Calipers
1. Rod.
2. Movable frame.
3. Barbell scale.
4. Sponges for internal measurements.
5. Sponges for external measurements.
6. Depth gauge ruler.
7. Nonius.
8. Frame clamp screw
1. Heel. 2. Subject of measurement. 3. Spindle. 4. Wheel. 5. Measuring scale (in mm). 6. Ratchet.
7. Nonius drum. 8. Staple.
When taking measurements, the subject (2) clamped between the heel and the micrometer screw (3). On the surface of the stem there are two dashed scales, shifted relative to each other by 0.5 mm, and having a division value of 1 mm. Drum (7) rotates around a circular scale, which is also located on the bevel of the drum. The micrometer screw can be fixed in any position. The screw is equipped with a ratchet mechanism to ensure a constant measuring pressure.
1. The object is installed between the heel and the micrometer screw, while rotating the drum, set the spindle on the approximate size of the object.
2. The spindle is carefully approached until it touches the object to be measured.
3. The size in mm is determined using the vernier of the drum, which corresponds to the horizontal index stroke of the stem scale.
4. The total size of the measured object is determined.
Note. When in contact with the measured object, do not press the spindle by rotating the drum sleeve by hand, this can lead to breakage of the micrometer. For more accurate sizing, you need to make sure that the item is well fixed.
The caliper is a versatile tool designed for high-precision measurements of external and internal dimensions. In addition, a caliper can determine the depth of holes and protrusions.
The measuring jaws of the caliper can also be used to measure the parallelism of the sides of workpieces. publishing house «Monolith»
Calipers have measurement limits of 0-125 mm (ShTs-1) , 0-160mm (ShTs-2) and 0-400 mm (ShTs-3).
The most commonly used caliper ShTs-1.
To measure external dimensions and control parallelism, the main measuring jaws of the tool are used, for measuring internal dimensions and marking, auxiliary pointed jaws are used.
Using a depth gauge, determine the depth of holes and protrusions.
The caliper device is based on a ruler with divisions (barbell) and an auxiliary scale-nonius, which moves along the main ruler-rod. With the help of this auxiliary scale, you can count the fractions of division of the main scale.
The principle of operation of the vernier is based on the difference between the division intervals of the main scale and the vernier scale. This difference is equal to the division price of the vernier, and the number of divisions depends on the division price.
If the scale division interval is 1 mm, and the vernier division interval is 0.9 mm, then the vernier division value is 0.1 mm.
Thus, if we combine the zero division of the vernier with the zero division of the main scale of the caliper, then the first division of the vernier «fall behind» from the first division of the main scale by the difference between the intervals of the scales, i.e. by 0.1 mm, the second division by 0.2 mm, etc.
The tenth division of the vernier, having shifted by 1 mm, coincides with the ninth division of the main scale of the rod, that is, if the division value of 1 mm is divided by the number of divisions of the vernier (on 10), we get 0.1 mm (see fig.)
Example:
If the zero stroke of the vernier coincides with any stroke on the ruler, then this/Division indicates the size in whole millimeters.
If the zero stroke of the vernier did not coincide with the stroke on the main scale, then the division on the ruler closest to the left shows an integer number of millimeters, and tenths are counted according to the vernier.
To an integer number of millimeters, as many tenths of a millimeter are added as the number of vernier strokes is counted until any stroke of the vernier coincides with one of the strokes of the ruler. The figure shows an example of reading 7 mm, and 7.7 mm.
Some calipers are equipped with a dial indicator. The indicator scale allows you to adjust the zero setting, control tolerances.
In the process of work and at the end of it, it is necessary to wipe the caliper with a cloth soaked in a water-alkaline solution, then dry with a clean cloth. At the end of work, cover the surface of the caliper with a thin layer of any technical oil and put it in a case. Avoid rough impacts or falls during operation in order to avoid bending of the rod and other damage, scratches on the measuring surfaces, friction of the measuring surfaces on the controlled part.
Dial indicator
The dial indicator is designed to measure linear dimensions by absolute and relative methods, to determine the magnitude of deviations from a given geometric shape and the relative position of surfaces. Indicators with a measuring range of 0-2 mm are available in two versions:
- ICH - with the movement of the measuring rod parallel to the scale;
- IT - with the movement of the measuring rod perpendicular to the scale.
The indicators are mounted either by a connecting sleeve with a diameter of 8h7, or by a lug 5 mm thick with a connecting hole with a diameter of 5 mm.
The use of the dial indicator is quite varied, so it is not described here. Specific cases of using the device are described in the repair manual (for example, measuring the end play of the crankshaft of an engine, measuring the runout of a brake disc, etc.).
Nutrometer
Bore gauge is designed to measure the internal dimensions of parts (for example, cylinder bore diameter, groove width, etc.).
1. Dial indicator.
2. Screw.
3. Handle.
4. Engine.
5. Centering bridge.
6. Tee.
7. Nut.
8. Measuring rod.
9. Fungus.
10. Rod.
11. Coil spring.
The device has a guide bush (5), in the upper part of which a dial indicator is installed (1), screw fixed (2). Inside the sleeve is a long rod that is in contact with a short rod (10), resting on the fungus (9) tee (6) caliper heads. The engine is located in the tee (4) and interchangeable measuring rod (8), fixed in the tee with a nut (7). On the side of the movable pin on the tee, a centering bridge 5 is mounted, which serves to install the indicator head along the diameter of the hole. When measuring holes, the slider (4) with coil spring (11) crushes the fungus (9) and through the rod (10) transfers the movement to a long rod to the indicator.
The deviation of the size is determined by the movement of the indicator arrow. Before measurement, the inside gauge is set to the nominal size along the ring or block of tiles.
Indicator calipers are produced with measurement limits: 6-10; 10-18; 18-35; 35-50; 50-100; 100-160; 160-250; 250-450 mm. For measurement, interchangeable washers and rods are attached to the inside gauge, differing from each other by 1 or 5 mm (depending on the measurement limit). The washers are installed in the hole of the head tee.